package org.apache.lucene.analysis;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.Reader;
import java.io.IOException;

/**
 * A Tokenizer is a TokenStream whose input is a Reader.
 * <p>
 * This is an abstract class.
 * <p>
 * NOTE: subclasses must override at least one of {@link #next()} or
 * {@link #next(Token)}.
 * <p>
 * NOTE: subclasses overriding {@link #next(Token)} must call
 * {@link Token#clear()}.
 */

public abstract class Tokenizer extends TokenStream {
	/** The text source for this Tokenizer. */
	protected Reader input;

	/** Construct a tokenizer with null input. */
	protected Tokenizer() {
	}

	/** Construct a token stream processing the given input. */
	protected Tokenizer(Reader input) {
		this.input = input;
	}

	/** By default, closes the input Reader. */
	public void close() throws IOException {
		input.close();
	}

	/**
	 * Expert: Reset the tokenizer to a new reader. Typically, an analyzer (in
	 * its reusableTokenStream method) will use this to re-use a previously
	 * created tokenizer.
	 */
	public void reset(Reader input) throws IOException {
		this.input = input;
	}
}
